Speedometer fix price???

[rvaedge]

Speedometer recalibration

I recently changed from the stock 235 75's to 31x10.5 on my x. the speedo is off about 3-5 mph im guessing. How much does it cost to have a shop recalibrate it??? Do they do it by a computer, or just by changing the speedo gear? Also, Ever since I put the new tires on the tranny seems to be shifting a little rougher? Is that normal? Also, in my case would the incorrect speedo give me the illusion of better or worse gas mileage? Thanks!

 

[00XLS]

On that year I believe the VSS vehicle speed sensor tells the speedometer how fast ect. Long story short you need to have the computer calibrated for the change in tire size, this can be done with power programmer, there are prob other means as well. I've never had to do this so I'm not sure but others will likely chime in.

 

[slravene]

you are most likely getting less mpg than before...obviously, but it shoudltn be much. Im not sure if the larger tires will affect the odometer and trip meter, someone else might though

 

[rvaedge]

I'm hoping it would be done by computer because it seems like that would be cheaper. To be more specific it is a 1997 v8 AWD explorer. Anybody know cost guestimate of what I will pay to have it recalibrated. Thanks again

 

[slravene]

depends on where you go i guess...ive heard that dealerships can charge in the ballpark of $90-$100. I dont know about other places. You just have to ask yourself is it worth it to spend the money on recalibration? Its not that far off and just remember to keep it slower and you will be fine.

 

[00XLS]

True, a local GM dealer around here was offering a tahoe with 20's on it as package, brand new. Told my best friends dad they couldn't refigure the speedo for the larger tires. I said what a bunch of horseshit, needless to say they didn't buy the truck.

 

[rvaedge]

I am wondering if the bigger tires threw off my transmission though. Ever since I put them on, the car has been shifting a little rougher. I've read that recalibrating the computer for larger tires can fix the shifting. Anyone know?

 

[00XLS]

Its possible, the computer tells the truck everything its doing. You've taken the parameters and messed with them without telling the computer.

 

[schmoken]

There's also Superlift's Truspeed unit. $170 in the catalogs.

http://www.superlift.com/products/misc/truspeed.asp

 

[ExplorerDMB]

I am wondering if the bigger tires threw off my transmission though. Ever since I put them on, the car has been shifting a little rougher. I've read that recalibrating the computer for larger tires can fix the shifting. Anyone know?

You are right, the Transmission does shift different. A little delayed accually (not slipping, just at the normal speed where it thinks it should). I bet if I can ever get mine squared away, my truck will be a little quicker with the 4.56s. Transmission goes with RPM, Speed, Throttle Position, etc -- so yes, your Transmission would be effected by the larger tires - computers are great, but sometimes they're hard to work with. Before I go further indepth with figuring out if my GEM Module needs to be replaced so I can reprogram, I am going to back door the program and go through the ABS system. Here is a link: http://www.explorerforum.com/forums/showthread.php?p=1298847

-Drew

 

[rvaedge]

Just to update, I put the 18 tooth speedo gear in (from ford dealership $9) and I definitely notice a difference in shifting. The hesitation that seemed to be there is now gone. I recommend the 9 bucks and 10 minutes of work to have a better driving car!

 

[Truck39Trash]

I have the same year and model x, I believed the speedo gear needed to be changed but I did not know exactly which gear I needed so thanks for posting that. I am assuming that the speedometer is accurate again in your x.
What color was the gear you got from ford yellow? or gray? Do you remember the part #
Does anyone have a picture of where exactly the gear is on the tranny or could tell a automobile illiterate like myself where it is?

 

[rvaedge]

No problem, I was pretty car illiterate before I joined the site and read a lot, but you learn as you go. I still dont know a third of the stuff most people know on here. Anyways, the speedo gear I got was yellow. Sorry I dont have the part number, but if you take the speedo gear off of your car and show the parts guy they should make sure the new one will work. It took me 3 dealerships to find someone who had it though, so it seems that they are few and far between! I want to reiterate that I am not sure how exact it got my speedometer. The only way for me to test it is by driving side by side with someone, talking on the cell to find out how fast we are going (havent had a chance to do yet). However, I'm sure because it smoothed out my shifting that it is much closer to correct than before. The picture below is of the transfer case. The speed sensor which is pointed out, is on the top of the tailhousing at the back of the transfer case. Take out the one bolt holding it on, give it a little tug (there will be an o-ring which also holds it on pretty snug) and you will see the speedo gear. Pop the black clip off which holds the gear on using a small screwdriver. Slide the old gear off, put the new gear on, put the clip back on, bolt the speed sensor back up, your done!!! Once you have the new gear it seriously take like 10 minutes to do. Ask me any more questions if you need. Good luck!

 

[storlied]

is it a gear or a computer change needed for the 98? what about 97? they're different afaik with the VSS and 4WABS..

Could someone explain the difference's a bit and tell me what exactly would need to be changed? The gear or a computer setting..

 

[gijoecam]

I want to reiterate that I am not sure how exact it got my speedometer. The only way for me to test it is by driving side by side with someone, talking on the cell to find out how fast we are going (havent had a chance to do yet). However, I'm sure because it smoothed out my shifting that it is much closer to correct than before.

It's much simpler than that and doesn't require another vehicle. The easiest way, of course, would be a GPS... However, you can do it yourself without one. Find a stretch of freeway that's relatively straight and flat. Stop next to a mile marker and reset your trip odometer. Drive 10 miles according to the mile markers on the freeway, then stop and read the odometer. That'll tell you exactly what percentage the speedometer and odometer are off by.

-Joe